linux-kernel - [PATCH 1/2] kexec: Disable in a secure boot environment

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Message-Id: <1359391662-26120-2-git-send-email-matthew.garrett@nebula.com>
Date:	Mon, 28 Jan 2013 11:47:41 -0500
From:	Matthew Garrett <matthew.garrett@...ula.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-efi@...r.kernel.org, linux-security-module@...r.kernel.org,
	Matthew Garrett <matthew.garrett@...ula.com>
Subject: [PATCH 1/2] kexec: Disable in a secure boot environment

kexec could be used as a vector for a malicious user to use a signed kernel
to circumvent the secure boot trust model. In the long run we'll want to
support signed kexec payloads, but for the moment we should just disable
loading entirely in that situation.

Signed-off-by: Matthew Garrett <matthew.garrett@...ula.com>
---
 kernel/kexec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 5e4bd78..dd464e0 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -943,7 +943,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 	int result;
 
 	/* We only trust the superuser with rebooting the system. */
-	if (!capable(CAP_SYS_BOOT))
+	if (!capable(CAP_SYS_BOOT) || !capable(CAP_COMPROMISE_KERNEL))
 		return -EPERM;
 
 	/*
-- 
1.8.0.2

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